Place:Cheve Cave, MexicoTeam:39 cavers from Poland, the Netherlands, Mexico, Australia, Spain, and the United StatesGoal:Establishing Cheve Cave as the world's deepest caveLast Attempt:In 2003 Stone led an expedition that put Cheve at its current depth, (4,869 feet [1,484 meters]), making it the deepest known cave in the Americas and the ninth deepest in the world.The Challenge:"To go all the way will be a 30-plus day journey in total darkness, beyond all hope of rescue. That call of the raw unknown has a certain subliminal beckoning to a rare few true explorers."These dispatches areedited versions of e-mail reports sent from the field. They have not been researched and represent the viewpoints and writings of individual expedition members.

Bill Stone's got one thing on his mind these daysgoing where no one has gone before. Until April, Stone and 40 international teammates will dive, rappel, hike, and dodge razor-sharp karst in hopes of breaking into Cheve Cave, deep in Mexico's Sierra de Juárez region. Its main system may have tunnels deeper than 6,500 feet (2,000 meters). If the team breaks into them, they could establish Cheve as the world's deepest known cave, bypassing Krubera Cave, in the Republic of Georgia. It currently holds the world record at 5,610 feet (1,710 meters). Check on the team's progress every week for the next eight weeks through dispatches and photographs (below) from the field. Then find out what Stone has to say about his seventh expedition to Cheve in a Question & Answer session.

An obnoxious mule's cries grabbed our attention early this morning in our dusty pueblo. Prying ourselves from our warm sleeping bags, we got up and started sorting a monstrous pile of gear while Bill Stone ventured out to get additional permission to start the expedition.

Since our ten mules were supposed to arrive at noon, we had to meticulously repack clothes, food, and gear into ten piles to last us for the next two weeks.

We're going to be at Star Gorge River Sink winching rocks, while simultaneously exploring Star Gorge Cave. If we break through, we might establish a permanent base camp there, and if we don't, then we'll decide whether to proceed with a diving endeavor at Aguacate River Sink.

When three men finally arrived with our mules, they laughed at our insurmountable piles of gear. The loads were very heavy and the mules were on the verge of their carrying capacity. One mule collapsed in the street after we strapped large Rubbermaid tubs to its sides and stacked 80-pound (40-kilogram) winches and bolting equipment on its back. The mule struggled getting back on all fours, then ate some grass to compensate for its dissatisfaction. Exhausted before we'd even began, we reloaded the trucks with the rest of our gear and tossed on our backpacks for a mud-slicked trail that led to our base camp.

We arrived almost two hours later and set up our tents. By dark, we had the generator running and were cooking up a hearty meal of potato, rice, and carrot grub. After some jokes and tall tales, we crashed to the comforts of our tents by 9:30 p.m. and caught up on some much needed sleep.

With base camp established, we began investigating Star Gorge, a spectacular shear-walled karst canyon. We'd heard that a local rancher had discovered something very unusual. Last October he was returning home from his fields at the height of the rainy season. The San Miguel River, which is the source for the water going into Star Gorge, had swollen to 20 times its dry season flow and the rancher heard a roar in the canyon. When he went to investigate, he discovered that an 82-foot (25-meter) diameter crater that was more than 39-feet (12-meters) deep, had suddenly appeared in the canyon floor, swallowing the river. Truck-size boulders had simply descended into a previously unknown subterranean void. Gregg Clemmer, Ryan Tietz, and David Kohuth went to locate this geologic event shortly after breakfast.

Gregg later related that there was indeed a major new sinkhole in the river and that it was a clean collapse with the river entering through large boulders. There were voids below, and Gregg carefully negotiated his way some 20 feet (five meters) down into it before deciding prudence was the better part of valor. The boulders were precariously balanced like marbles in a jar, and removing one could send hundreds of tons of rock downward. It's likely the collapse was triggered by a roof breaching in a large cave passage below. What remains will be an engineering challenge because these boulders will have to be picked out one by one. We have a pair of five-ton (four-metric ton) winches in camp, explicitly for this purpose.

John Kerr, James Brown, Andi Hunter, and I went on to Star Gorge Cave and removed some logs blocking the entrance. Our objective for the day was to enlarge a crawlway about 300 feet (100 meters) into the cave, so the crew could easily pass with large duffel bags of equipment. We spent nearly an hour moving sand and fist- to bread loaf-size rocks until we'd made the tunnel large enough for us to walk through ducking. We then continued on another 300 feet (100 meters) to the first rope dropa 20-foot (five-meter) pothole carved by the ancient river that ran through the cave. Star Gorge Cave is third in a chain of places where the San Miguel River enters into the Sierra de Juárez. The sand and gravel deposits blocking the various sections of the tunnel in the cave are simply places where some flood from 100,000 years or so ago brought in copious quantities of sediment, dropping it into the cave's low spots. Similar sand piles exist all along the arroyo outside the cave.

Tomorrow our plan is to send the entire team to Star Gorge Cave, so we can start working at the end of the cave, 1,600 feet (500 meters) in from the entrance.

We spent the morning sorting rope lengths for three vertical drops, organizing parts for the rebreather (a diving apparatus used to absorb carbon dioxide and recycle usable oxygen), and assembling vertical systems. We also ran through a practice rebelay (re-anchoring of ropes). This is an important technique that creates diversions around obstacles and establishes rigging at the top of vertical drops.

The first team (John Kerr, Jan Matthesius, Pauline Berendese, David Kohuth) headed out of base camp around noon toward Star Gorge Cave. The second team (Bill Stone, Ryan Tietz, James Brown, and I) headed down soon after. Two new cavers, Nathan Noble and Mike Frazier, caught up with us. They've already been out in the field for four weeks and their clothes and vertical gear were ragged and torn. Give us another three weeks and our team will look the same.

Frazier took the lead into the cave and Noble followed. Once all three vertical drops were rigged, I helped them start digging on constrictions that were disabling airflow to the end of the cave. Meanwhile, other team members went to the prime digging site to start hauling out buckets of soil. With fingers worn and joints aching, we headed out of the cave and arrived at base camp at 11:17 p.m.

Yesterday five cavers from Poland arrived and we more than welcomed their help, especially after a long day of digging yesterday. Today we're hoping for more normal work hours, which means at least four hours of hiking and caving and seven hours of digging. Some of us started off first to Star Gorge Cave and we had a nice hike. The foggy and humid weather had cleared up and the coffee plants, bamboo, and grassy fields made for beautiful scenery.

Once we got to our destination and the Polish cavers and John Kerr had joined us, a group went all the way to the end of the dig and started passing out buckets of rocks and dirt. We worked steadily, but hard, thinking of what we might discover. While catching our breath in between pulls, we even managed to get in a few humorous conversations. That's the fun part of working on a project like this. While we're all different nationalities, we're also a lot alike because we're cavers. I think Gregg got it right with, "A famous mountaineer once said, 'I have to climb that mountain because it's there.' Cavers say they go caving because it MIGHT be there."

Pauline Berendese

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Jim Brown, Ryan Tietz, Andi Hunter, and I manned base camp today, mainly catching up on gear preparation and doing laundry in the San Miguel River. Ryan spent most of the day unraveling a kilometer-long length of dive line, some of which will be used in Star Gorge Cave for tag lines when we're hauling out buckets of debris.

News of our presence in the region has spread, and the number of daily visitors to our base camp has increased. Today five local villagers from Santa Ana stopped by. When the conversation turned to caves, a few said they knew of a cave some 15 minutes up the valley from base camp. Three of them, who were hunters, said they would be willing to guide us there tomorrow. This is one of the strokes of luck that occasionally happens on an expedition. We might spend weeks chopping through the jungle, searching for entrances, and then a single chance meeting produces knowledge we never would have gained otherwise.

If there is a cave there that continues downward, it would be an extraordinary find for us since it would be nearly on top of the limit of exploration in Charco Cave, one of the major caves in the Sistema Cheve area.

After intense digging in the low bottom passages of Star Gorge Cave, we focused our efforts on the river sink 1,600 feet (500 meters) upstream from the cave. The dramatic stream collapse that had happened farther upstream last fall had pirated the entire water flow into an unknown cave. When this was initially investigated, it was too unstable to dig at.

Today our dig at Star Gorge River Sink is dry, and more subtle signs confirmed our suspicions that this is a superb place to dig. Broken bamboo lay piled against one corner of the northern headwall, indicating the water's swirling path into the underground. Soft, deep sand stood banked underneath. The initial digging would be easyor so we thought.

Dave Kohuth, John Kerr, James Brown, and I began the dig by clearing the bamboo and sand. Somewhere underneath, water had disappeared from the riverbed, leaving the arroyo full of dry river rock. Excavating took us down four feet (1.2 meters) of sand. A solution crack opened on our right, a joint in the limestone that had been filled with sand, rotting leaves, sticks, and assorted trash. Ryan joined the crew in mid-afternoon. About dark, I pushed my crowbar through into a void. Initial excitement gave way to more hard work. The opening was quickly cleared to reveal a clean-washed cave passage. Still, it looked far too tight to enter, but when we peeked beyond, the passage appeared to open up.

February 20, 2004: Tight SqueezesWe went at the dig again at Star Gorge River Sink, taking out rock in chunks with drills and chisels. Andrea also helped out by worming her way into the tightest section, head down, and handing back rocks. She filled bucket after bucket with sand and muck, lowering the floor and widening the passage for the rest of the crew. We began a second dig about 13 feet (four meters) to the left of the first dig. This, according to Bill Stone, was where the water had been noted sinking the previous year. Ominous large boulders the size of cement trucks stood poised above this potential dig. Safety being paramount, we kept a keen eye on the rocks wedged above us. I crawled into the small space, finding hundreds of daddy longlegs covering the low ceiling. When I moved forward, the slightest disturbance sent the whole colony into a pulsating, dancing arachnid mass. But when I froze, the moving spider wall calmed into stillness. It was then I noted the very definite presence of a cool breeze!

For cave diggers this is one of the golden clues to finding open cave passages. Where water had vanished in ages past, air now exited from unknown voids deep in the limestone mountain. Our dig would focus on following the air.

Six teammates (Tomek Fiedorowicz, Pavo Skoworodko, Andi Hunter, Artur Nowak, Malgorzata Barcz, and Kasia Okuszko) and I hiked up the mountain to Santa Ana at dawn. The previous day Tomek and Pavo had hiked some two hours at a fast pace down the high trail toward the village of Chiquihuitlán, about 700 feet (200 meters) above the Star Gorge River Sink on the north side. There a local farmer showed them a deep pit. It turned out, through GPS measurements, that the pit was located relatively close to a dirt road on the north side of the ridge that connects Chiquihuitlán to Cuicatlán.

From Santa Ana we drove a half hour east before pulling off onto the steep mountainside. From there a deeply rutted trail led southwest over the ridge pass and then down to the pit. Tomek proceeded to rig the entrance shaft, while trailing a duffel bag filled with 650 feet (200 meters) of rope in a single piece. Two rebelays were set and then there was silence for some time before we heard the echoing word "volna," which is Polish for "off rope," coming from below. Pavo and Andi went down and then I was next. It was an impressive drop, free fall all the way with light rays penetrating down into the gloom.

When I touched down, Tomek informed me that the cave had ended and that he and Pavo had explored a deeper chamber below where the rope landed. There was some apprehension among the survey party after Pavo pointed out the presence of some very large spiders at a number of locations on the wall, along with blue and yellow millipedes measuring upward of ten centimeters (four inches) in length. We proceeded across the floor of the pit and down into a fissure leading to a chamber some 70 feet (20 meters) lower. After Pavo set the first survey station in the fissure, everyone descended rapidly. Down below was a 70-foot (20-meter) diameter chamber with a deep mud floor that was dried and cracked.

Back at the entrance pit Andi and I tandem climbed the ropeone above the othersince our 100-foot (30-meter) tape was too short to measure the entire drop in one shot. So Andi would climb about 70 feet (20 meters) up and I would follow, marking each measurement in the book. The first bolt was 199.1 feet (60.7 meters) off the floor, entirely free fall. Another 70-foot (20-meter) shot got us to the lip of the entrance. The total depth, later computed at base camp, was 301 feet (92 meters).

Bill Stone

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Today some of my teammates and I went after both digs with a vengeance. The left dig held the most promise because of the noted airflow that increased as we dug. The one on the right had ample evidence of limestone solution, indicating that we were also digging in a good spot.

After several hours of handing out rocks and other debris, I cleared a small cave (measuring 15 feet [five meters]deep by an irregular diameter of two to three feet [0.6 to one meter]) in the left dig, which angled down into more broken rock. Thankfully, the arachnid occupants had vanished. But more importantly, there were numerous blowing holes. This was strong evidence of an open conduit to cave passage beneath, so we pushed the dig deeper.

After eight hours of backbreaking labor, we closed down the operation for the night and left the work site encouraged by the progress we'd made. Even the right dig offered a faint breeze from the unknown. Perhaps tomorrow will bring discovery!